Critical current survival in the YBCO superconducting layer of a delaminated coated conductor

Abstract

High temperature superconducting coated conductor (CC) could be practically applied in electric equipment due to its favorable mechanical properties and the critical current performance of YBCO superconducting layer. It is well known that CC could be easily delaminated because of its poor stress tolerance in thickness direction, i.e. along the c-axis of YBCO. Commonly, a stack including YBCO layer and silver stabilizer could be obtained after the delamination. It would be interesting to investigate the superconducting properties of the delaminated stack, since it could also be considered as a new type of CC with the silver stabilizer as the buffer layer, which is quite different from the oxide buffer layers in the traditional CC and might lead to new applications. In this study, a CC sample was delaminated by liquid nitrogen immersing. A Hall probe scanning system was employed to measure the critical current (IC) distribution of the original sample and the obtained stack. It was found that IC could be partially preserved after the delamination. Dense and crack-free morphologies of the delaminated surfaces were observed by scanning electron microscopy, and the potential application of the obtained stack in superconducting joint technology was discussed.

Magnetization and screening current in an 800 MHz (18.8 T) REBCO nuclear magnetic resonance insert magnet: experimental results and numerical analysis

“…The model focuses on the hoop stress on macroscale, under which the I c degradation of REBCO tape is measurable [53], to determine whether the REBCO tape is at risk of being overstressed. However, the potential damage inside the coated conductor due to the concentration of Lorentz force and difference in mechanical properties between layers, such as delamination [54][55][56], are not within the scope of this analysis.…”

An efficient approach for superconducting joint of YBCO coated conductors

“…However, the achievement of superconducting joints with high I c is still a challenge, because the biaxial texture and superconducting phase between two REBCO layers need to be formed after the joining procedure. In addition, it is difficult to introduce oxygen into the joining region for restoring the superconductivity of the REBCO layer due to the extremely low diffusion coefficient of oxygen in the REBCO layer [16].…”